1. Field of the Invention
The present invention relates to a device having a tube for heating or heat-retaining of fluid such as gas and liquid by a cord heater inserted into the tube (hereinafter referred to as a heating/heat-retaining tube) through which the fluid is transported.
2. Description of the Related Art
This type of devices having a heating/heat-retaining tube include those already developed and filed for patent application by Japanese Patent Application Laid-Open (kokai) No. 2005-351333.
The above described heating/heat-retaining tube has various merits including, for example, low cost, small outer diameter, and suitability to complex piping layouts.
Meanwhile, in the device having the heating/heat-retaining tube, as shown in FIG. 5, one end of a lead wire LW is connected to the power supply P and the other end is connected to the cord heater CH which is led out of a tube joint. The connection area of the lead wire LW and the cord heart CH has the following configuration. Specifically, as shown in FIG. 6, in this configuration, two cap bodies 90 and 91 made of a resin material such as nylon or a fluorine resin are mutually screwed (with a female screw 92 and a male screw 93) so as to form a space section 94, a connecting section t of the lead wire LW and the cord heater CH is housed in the space section 94, and fluid is prevented from penetrating into the space section 94 by two O-rings 95 and 96 made of silicon. For attachment to a tube section 100, an O-ring 97 is provided on the inner wall of the tube section 100 to ensure airtightness mutually between the inner circumferential wall of the tube section 100 and the outer circumferential wall of the cap body 91.
However, in the above described connecting section t, the lead wire LW and the cord heater CH are bonded to each other merely by soldering the lead wire LW and the cord heater CH after removing the resin cover therefrom. Therefore, if the O-ring 96 on the cord heater CH side is, for example, deteriorated, gas or liquid may penetrate into the space section 94 and then into the cord heater CH or the lead wire LW. This causes an electrically dangerous situation and possibly damaging the entire system.
Therefore, a device is developed having a heating/heat-retaining tube which prevents gas or liquid from penetrating into the space 94 having the connecting section t of the lead wire LW and the cord heater CH.